The average temperature of the first three days of a week is 27°C.
The average temperature of the next three days is 29°C.
The average temperature of the whole week is 28.5°C.
What is the temperature on the last (7th) day of the week?

1. A

   31.5°C

2. B

   28.0°C

3. C

   42.0°C

4. D

   26.0°C

Appeared in: BSF Staff Nurse - 2015

Explanation

• The total temperature for the entire week (7 days) is the average weekly temperature multiplied by 7 (28.5°C × 7 = 199.5°C).
• The total temperature for the first 6 days is the sum of the totals for the first three days (27°C × 3 = 81°C) and the next three days (29°C × 3 = 87°C), which equals 168°C.
• To find the temperature of the last day, subtract the total temperature of the first 6 days from the total temperature of the entire week (199.5°C - 168°C = 31.5°C).

Why Other Options Were Wrong

• Option B: This value is close to the given average temperatures but does not result from a correct calculation. It ignores the weighted impact of the different averages over the specified periods.
• Option C: This value is significantly too high and would result from a major calculation error, such as incorrectly summing or multiplying the given averages without considering the number of days.
• Option D: This value is lower than any of the given averages for the periods. A calculation error, such as subtracting values in the wrong order, might lead to such an incorrect answer.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculating a missing value from a set of averages as background academic context rather than a clinical decision trigger.
• While this is a mathematics question, the ability to calculate and interpret averages is a fundamental skill in nursing.
• This skill is essential for tasks like monitoring patient trends (e.g., average blood pressure over a week), calculating medication dosages over time, and understanding fluid balance charts.
• What if? If the average for the whole week was 28.0°C instead of 28.5°C, the total weekly temperature would be 28.0 x 7 = 196°C. The last day's temperature would then be 196°C - 168°C = 28.0°C.

How to Approach the Question

• First, identify the goal of the question, which is to find the temperature on the last (7th) day.
• Recall the formula for finding a total from an average: Total = Average × Number of Items.
• Calculate the total temperature for the whole week (7 days) by multiplying the weekly average by 7.
• Calculate the total temperature for the first 6 days by summing the totals of the two 3-day periods.
• Subtract the 6-day total from the 7-day total. The result is the temperature of the 7th day.
• Finally, compare your calculated result with the given options to select the correct answer.

Concept Tested & Keywords

• Concept Tested: Calculating a missing value from a set of averages.
• Stem keywords: average temperature, first three days, next three days, whole week
• Lead-in keywords: What is

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QKGyzXhBIZsbqtPf_RslPh

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